Dear Colleagues,
My co-authors and I are pleased to announce that a new publication is now available:
Holt,
M.M., Ghoul, A., and Reichmuth, C.J. 2012. Temporal summation of airborne tonal
signals in a California sea lion (Zalophus
californianus). Journal
of the Acoustical Society of America 132: 3569-3575.
ABSTRACT:
The trade-off between sound level and
duration on hearing sensitivity (temporal summation) was investigated in
a California sea lion (Zalophus californianus)
using airborne pure-tone stimuli. Thresholds were behaviorally measured
using the method of constant stimuli at 2.5, 5, and 10 kHz for nine
signal durations ranging from 25 to 500 ms. In general, thresholds
decreased as duration increased up to 300 ms, beyond which thresholds
did not significantly improve. When these data were fitted separately to
two versions of an exponential model, the estimated time constants
(92–167 ms) were generally consistent between the two fits. However, the
model with more free parameters generated fits with consistently higher
R2 values,
while avoiding potential arbitrary decisions about which data to
include. The time constants derived for the California sea lion were
generally consistent with those reported for other mammals, including
other pinnipeds. The current study did not show a clear correlation
between time constant and test frequency. The results should be
considered when conducting audiometric work, assessing communications
ranges, and evaluating potential noise impacts of airborne tonal signals
on California sea lions.
©
2012
Acoustical Society of America
The full article can be found online at:
http://asadl.org/jasa/resource/1/jasman/v132/i5/p3569_s1
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__________________________________
Marla M. Holt, Ph.D.
Research Wildlife Biologist
Marine Mammal & Seabird Ecology Team
Conservation Biology Division
NOAA/NMFS Northwest Fisheries Science Center
2725 Montlake Blvd East
Seattle, WA 98112
Phone: 206.860.3261
Fax: 206.860.3475
www.nwfsc.noaa.gov/research/divisions/cbd/marine_mammal/marinemammal.cfm